This exhibit focuses on the floodplains in Great Seneca Stream Valley Park & North Germantown Greenway Park. Floodplain benefits revealed during peak flood events are captured on April 30 & May 16, 2014. Maps show where proposed M-83 Master Plan Alignment would impact multiple floodplain areas within Great Seneca Creek Watershed. To construct M-83 through these forested ecosystems would accelerate peak storm water discharge downstream.
These are the important details for you to see from the map 470 ft. Drop from Damascus to Montgomery Village,
Reiterate that these are the A,B,C Bridges from beginning slide. Upcoming Photographs Identify a “Working” Floodplain.
Talk about what I photographed. The road takes the wider girth. The impact is significant along this flood plain. A neighborhood is split in half
The good things about this watershed.
To the Left of picture the deforested hill will be an advantage for the highway because it is on top of the slope, but a disadvantage to the creek because the runoff will go directly into the creek. A wall will create a slump. Note 2:The Golf Course was recently bought by a developer. Increased runoff from new development will affect the current floodplain.
This is a second example of the Floodplain at work. Note the railing in both pictures.
Note That Dayspring Convergence is North of picture, and only Great Seneca Creek is shown. At this halfway point from Damascus, Dayspring, Wildcat Branch, Magruder Branch, and Goshen Branch have already merged. What we see is the smaller North Creek coming from East Village and Great Seneca From the North. Note 2: The M-83 running inside the wooded park and parallel to Great Seneca Creek will be dumping sediment into the water.
This is a tremendous amount of Clean Water
Note that Bridge C is at the bottom of this map, and we are looking at Several source streams. Also Note the Dayspring Silent Retreat Center is located in N. Germantown Greenway Park, and they have submitted 20 years of Invertebrate data showing a stream in good condition. Wildcat Branch is also in good invertebrate condition according to the state 2012 data.
M83 Flood Plain Impact
AN EXHIBIT TO REMOVE PROPOSED M-83 EXTENDED
Data & Photographs Present Compelling Evidence
to Support the Removal of “Proposed M-83 Extended”
from the Master Plan of Highways & Transitways
for Montgomery County, MD
ANN SMITH: Author, Biologist & Photographer
EDNA MILLER: Editor & Graphic Artist
TAME COALITION: Sponsor
TAME Coalition is raising public awareness about the destructive
environmental impacts of proposed Mid-County Highway Extended
This exhibit focuses on the floodplains in Great Seneca
Stream Valley Park & North Germantown Greenway Park.
Floodplain benefits revealed during peak flood events are
captured on April 30 & May 16, 2014.
Maps show where proposed M-83 Master Plan Alignment
would impact multiple floodplain areas within Great Seneca
Creek Watershed. To construct M-83 through these forested
ecosystems would accelerate peak storm water discharge
In this “Exhibit To Remove M-83 Extended”
• GOOGLE MAPS LOCATE:
– Site of each peak flood event photographed from three Watkins Mill Road
bridges over tributaries of Great Seneca Creek.
– Route proposed for M-83 Extended through the length of Great Seneca
Stream Valley Park & across North Germantown Greenway Park.
– The proximity of Dawsonville Gauge at the confluence of Little Seneca Creek
with Great Seneca Creek as comparable with the elevation drop (gradient) of
Exhibit sites marked bridges “A”, “B” & “C”.
• PHOTOGRAPHS SHOW: compelling examples of peak flood water
spreading across floodplains, which slows down velocity and drops sediment.
• CHARTS CONNECT: Dates from the Dawsonville Gauge readings in cubic
feet per second (CFS) align with this Exhibit’s photography dates.
The floodplain degradation and deforestation
of building M-83 would cause increased storm
water runoff surges in the following tributaries:
1) Dayspring Creek runs through North
Germantown Greenway Park
2) Wildcat Branch converges with Great Seneca
Creek above Brink Road
3) Brandermill Run enters Great Seneca west of
4) Cabin Branch Stream enters Great Seneca
west of Bridge “B”
5) Whetstone Run enters Great Seneca west of
6) Walkers Run enters Whetstone Run southeast
of Bridge “A”
Proposed M-83 would NOT reduce sediment
loads into the Potomac River & Chesapeake Bay.
INTRODUCTION TO IMPACTED FLOODPLAINS OF GREAT SENECA CREEK
& ITS TRIBUTARIES IF M-83 EXTENDED IS CONSTRUCTED
DISCOVERING FLOODPLAINS AT CAPACITY
It was alarming to see how close raging floodwaters came up to this Watkins Mill Road bridge,
over a tributary of Great Seneca Creek.
Great Seneca Creek starts at Mount Lebanon in Damascus, (787 Ft. Elevation), runs
through this mid-point location along Watkins Mill Road & ends at the Potomac. 5
Google Maps Used In This Exhibit Identify:
1. ELEVATIONS ABOVE SEA LEVEL: For Great Seneca Creek & its tributaries
gradient; elevations explain the levels flood waters must drop from
Damascus to Montgomery Village, then to Dawsonville.
2. WATKINS MILL ROAD: Although a distance from the Dawsonville Gauge (CFS
Data Source), peak flood volume shown by its gradient is comparable to the
Gauge’s readings on the matching dates in the Exhibit.
3. PROPOSED M-83 EXTENDED ROUTE: Is perpendicular to tributary flood-plains
near Watkins Mill Road bridges, runs parallel through Great Seneca
Stream Valley Park & perpendicular to North Germantown Greenway Park.
4. GREAT SENECA CREEK FLOODPLAINS & TRIBUTARIES: M-83 would degrade
multiple floodplains’ ability to slow down peak flood events. M-83 would
accelerate peak flood velocity, which would carry greater amounts of
sedimentary load downstream.
Elevations from Damascus to “Proposed M-83” represent a larger gradient drop than those
leading from Montgomery Village to the Dawsonville Gauge
Elevation 308 ft
These readings represent similar characteristics of the flood volume
shown in Exhibit photographs, taken from Watkins Mill Road bridges. USGS
has been monitoring the gauge for over 80 years.
The researched data from this flood gauge is used in this chart. The next
chart shows just how extreme flood volume has been.
With ‘Five Annual Peak Flood (CFS) Readings’ from the Gauge’s historic
record, and readings for the two photography dates, the chart shows a
trend of extremely high levels of peak flooding in cubic feet per second.
WHY USE THE DAWSONVILLE GAUGE FLOOD DATA?
USGS DISCHARGE READINGS FROM DAWSONVILLE GAUGE
ALIGN WITH PHOTOGRAPHS TAKEN IN THIS EXHIBIT
At flood stage is
6,220 (CFS) 7,040 (CFS)
120 (CFS) AVERAGE
8280 FIVE YEARS
Cubic Ft Per Second
OF PEAK FLOOD
COMPARED TO FLOOD VOLUME IN THIS EXHIBIT
A TREND IN ANNUAL PEAK FLOOD VOLUME
FUTURE EXIT 12
Blohm Valley Park
A CLOSE-UP FROM BRIDGE “A” – WHERE STORM WATER FLOWS ACROSS
FLOODPLAINS IN RELATION TO M-83 ROUTE
VIEW FROM BRIDGE “A” – CAPTURED AT WHETSTONE RUN & BLOHM PARK
An example of a stream’s capacity inside the banks of a snake curve
showing a natural meander that slows water and drops sediment.
VIEW FROM BRIDGE “A” – AT WHETSTONE RUN IN FLOOD
Water flows West across the floodplain to spread out, slow down & drop sediment.
Evidence of how vegetation and trees naturally absorb water above banks of Run.
April 30, 2014
Example of sediment & debris that settled after a flood at the Blohm Park, showing the
efficiency of trees, shrubbery and grasses to relieve storm water of its load.
VIEWED FROM BRIDGE “A” – AT WHETSTONE RUN & BLOHM PARK
VIEW WEST OF BRIDGE “A” – FLOOD CAPTURED AT WHETSTONE
RUN FROM THE GAZEBO AT BLOHM PARK
Current overflow from Lake Whetstone into Whetstone & Walkers Run crosses the forested floodplain of
proposed M-83 Extended Route. Its culverts and pavement would eliminate this floodplain benefit.
APRIL 30, 2014
VIEW IS EAST OF BRIDGE “A” – CAPTURED DURING THE SECOND FLOOD EVENT
Flood reaches ‘South Valley Park Ball Field’
in Montgomery Village
Peak storm water spreading across
floodplain where trees, grasses &
vegetation filter sediment.
THE HISTORY OF BRIDGE “A” – WHETSTONE/WALKERS RUN
NEAR WATKINS MILL ELEMENTARY SCHOOL
This 1997 bridge design was
based on the County Council’s
1992 decision not to include the
proposed M-83 .
Six people were almost swept away in 1987 by the swift current at
Whetstone Run in Montgomery Village, Maryland.
PICTURE SUBMITTED BY JANE WILDER
MAP SHOWS BRIDGE “B” – WATER FLOW OF CABIN BRANCH & GREAT SENECA CREEK
Cabin Branch Stream flowing across Montgomery Village Golf Course
VILLAGE GOLF COURSE
CABIN BRANCH STREAM
ADJACENT TO BRIDGE “B” – VIEWS OF MONTGOMERY VILLAGE GOLF COURSE
Two Geese and a Heron enjoy the flooded landscape
APRIL 30, 2014
High levels of flood waters cross floodplain, as water spreads out sediment drops.
NEAR BRIDGE “B” – SHOWS THE SAME VIEW OF CABIN BRANCH TRIBUTARY
“At Flood” and “Dry” across floodplain, taken from the same hill near bridge “B”
AT FLOOD ON APRIL 30, 2014
(6,220 CFS) DRY ON AUGUST 7, 2014
LOCATION OF BRIDGE “C” COMPARED TO PROPOSED M-83 ROUTE
After the confluence of Dayspring Creek and Great Seneca Creek
VIEWS OF BRIDGE “C” DURING SECOND FLOOD EVENT
These pictures show flood event at capacity below the confluence of
Great Seneca Creek and North Creek. Also shows the accumulative affect of storm water
moving down Great Seneca Creek that started near Damascus at Mt. Lebanon.
VIEWS NEAR BRIDGE “C” – PICTURES TAKEN FROM HILL OVERLOOKING THE FLOODPLAIN
Second Flood Event on May 16, 2014 August 7, 2014
Note the height of the fenced-in boxes.
They are part of WMET Radio Towers
located at Great Seneca Creek bridge “C”.
M-83 IMPACT ON NORTH GERMANTOWN GREENWAY PARK
If proposed M-83 were built through North Germantown Greenway Park, it would clear
cut the interior forest & accelerate flood waters beyond capacity to bridge “C” site.
REMOVING M-83 IS THE SOLUTION
• Without the full support of these existing forested
floodplains, critical conditions for stream flow and
sedimentary load downstream could only increase.
• M-83 development will not benefit Maryland’s
measureable goal of reducing sediment load in the
Great Seneca Creek Watershed.
• To remove Mid-County Highway Extended (M-83) from
the Master Plan of Highways & Transitways would
ensure forested floodplains continue their function.
• State Law: ww.mde.state.md.us/Seneca_Sed_TMDL_093011_Final.pdf
• EPA: www.epa.gov/Seneca Creek Sediment TMDL_combo.pdf
ACKNOWLEDGEMENT OF THANKS TO TAME COALITION TEAM VOLUNTEERS:
Margaret Schoap, Richard & Jane Wilder,
Bing Garthright & Patty King, Lauren & Dale Smith